1. Field of the Invention
The present invention relates to an electromagnetic shield structure of an electronics housing for blocking an electromagnetic wave between the electronics and the outside thereof.
2. Description of the Background Art
The electronics having a connection terminal connected to the outside is generally disposed within a housing because exposure of the electronics to the outside during use leads to a decrease in durability and operability. Furthermore, the electronics are surrounded by an electromagnetic shield such that the electronics are electromagnetically shielded from the outside.
There may be a case where the electromagnetic shield is provided with a function as an electromagnetic shield by forming a thin film having conductivity and electromagnetic-wave shielding properties on the inner surface of the housing, providing a protrusion having a shape of a flat spring on the periphery of a connection terminal, and bringing the protrusion into contact with the inner surface of the housing for achieving conduction. In recent years, however, the electromagnetic shield may often be made of a plate-shaped metal member subjected to bending and provided separately from the housing, in consideration of the environmental load of the plating process when forming a conductive thin film on the inner surface of the housing.
The electronics housing equipped with a connection terminal has conventionally been integrally molded in the shape of a box with resin and the like. Japanese Patent Laying-Open No. 2005-85831 is one of the prior art documents disclosing such an electronics housing. The electronics housing disclosed in this document includes a housing body through which a connection terminal connected to the outside is exposed, and a cover member attached to the housing body and covering the connection terminal. The electronics housing also has a stepped portion inwardly concaved so as to surround the connection terminal, and an engagement portion formed on the surface provided with a leg of the housing body and on the surface of the stepped portion approximately parallel to the surface provided with the leg. When the cover member is attached, it engages with the engagement portion.
The stepped portion inwardly concaved so as to surround the above-described connection terminal serves to fill the gap between the protrusion of the connection terminal and the outer surface of the housing. The presence of the gap may result in adherence of dust and the like to the electronics, and also may impair the appearance.
Furthermore, there may also be a case where a baby's finger or the like is accidentally inserted into the gap. Thus, the gap should be filled without fail.
The electronics housing consists of a plurality of components. According to the electronics housing disclosed in the above-described document, the stepped portion inwardly concaved so as to surround the connection terminal is formed in a rear case. The components constituting the housing are often manufactured by injection molding of resin material, in which case a mold for injection molding is required for manufacturing the housing.
Generally, a core mold, a cavity mold and a slide mold are required for manufacturing the component such as a rear case accommodating the connection terminal. In this case, the core mold is a male mold, the cavity mold is a female mold, and the slide mold is a mold which is movably placed in the portion between the core mold and the cavity mold into which resin is injected. The outer contour of the rear case including a shape of a concave portion is determined by the core mold and the cavity mold. The position or the shape of the opening accommodating the protrusion of the connection terminal is determined by the slide mold.
Since there are various types and sizes of connection terminals, the rear case should be manufactured to have a shape accommodating the connection terminal. Specifically, a change in shape of the protrusion of the connection terminal creates a need to reflect the change of the shape in the slide mold. Also, a change in the shape of the gap between the housing and the connection terminal creates a need to reflect the shape complementing the gap in the core mold and the cavity mold. Accordingly, there is a need to manufacture each of a core mold, a cavity mold and a slide mold used for producing a rear case, so as to accommodate the shape of the connection terminal.
According to the electronics housing disclosed in the above-described document, all of the core mold, the cavity mold and the slide mold for the housing components accommodating the connection terminal should be newly manufactured in accordance with a change in the type of the connection terminal to be attached. Thus, even a slight change in the shape of the connection terminal requires at least three molds to be produced accordingly, which results in an increase in cost for the electronics housing.